背景：
项目中遇到了网页截图的场景，开始使用了html2canvas ，本地一切都好，但正式环境中出现问题，dom中有图片，以为是这些图片跨域，最后按照解决办法也不行；再后来又看到是dom要设置宽高，但试过依旧不可以。最终换个库来实现需求
dom-to-image
github: https://github.com/tsayen/dom-to-image
后来发现了基于此库的新项目 dom-to-image-more（https://www.npmjs.com/package/dom-to-image-more）
改造
项目中使用发现清晰度有点低，客户也指出来，但这个库貌似并没有相关配置可以实现，无奈只得开始对其进行修改
文件替换
文件路径： node_modulesdom-to-imagesrcdom-to-image.js
代码语言：javascript复制(function (global) {
'use strict';
var util = newUtil();
var inliner = newInliner();
var fontFaces = newFontFaces();
var images = newImages();
// Default impl options
var defaultOptions = {
// Default is to fail on error, no placeholder
imagePlaceholder: undefined,
// Default cache bust is false, it will use the cache
cacheBust: false
};
var domtoimage = {
toSvg: toSvg,
toPng: toPng,
toJpeg: toJpeg,
toBlob: toBlob,
toPixelData: toPixelData,
impl: {
fontFaces: fontFaces,
images: images,
util: util,
inliner: inliner,
options: {}
}
};
if (typeof module !== 'undefined')
module.exports = domtoimage;
else
global.domtoimage = domtoimage;
/**
* @param {Node} node - The DOM Node object to render
* @param {Object} options - Rendering options
* @param {Function} options.filter - Should return true if passed node should be included in the output
* (excluding node means excluding it's children as well). Not called on the root node.
* @param {String} options.bgcolor - color for the background, any valid CSS color value.
* @param {Number} options.width - width to be applied to node before rendering.
* @param {Number} options.height - height to be applied to node before rendering.
* @param {Object} options.style - an object whose properties to be copied to node's style before rendering.
* @param {Number} options.quality - a Number between 0 and 1 indicating image quality (applicable to JPEG only),
defaults to 1.0.
* @param {String} options.imagePlaceholder - dataURL to use as a placeholder for failed images, default behaviour is to fail fast on images we can't fetch
* @param {Boolean} options.cacheBust - set to true to cache bust by appending the time to the request url
* @return {Promise} - A promise that is fulfilled with a SVG image data URL
* */
function toSvg (node, options) {
options = options || {};
copyOptions(options);
return Promise.resolve(node)
.then(function (node) {
return cloneNode(node, options.filter, true);
})
.then(embedFonts)
.then(inlineImages)
.then(applyOptions)
.then(function (clone) {
return makeSvgDataUri(clone,
options.width || util.width(node),
options.height || util.height(node)
);
});
function applyOptions (clone) {
if (options.bgcolor) clone.style.backgroundColor = options.bgcolor;
if (options.width) clone.style.width = options.width 'px';
if (options.height) clone.style.height = options.height 'px';
if (options.style)
Object.keys(options.style).forEach(function (property) {
clone.style[property] = options.style[property];
});
return clone;
}
}
/**
* @param {Node} node - The DOM Node object to render
* @param {Object} options - Rendering options, @see {@link toSvg}
* @return {Promise} - A promise that is fulfilled with a Uint8Array containing RGBA pixel data.
* */
function toPixelData (node, options) {
return draw(node, options || {})
.then(function (canvas) {
return canvas.getContext('2d').getImageData(
0,
0,
util.width(node),
util.height(node)
).data;
});
}
/**
* @param {Node} node - The DOM Node object to render
* @param {Object} options - Rendering options, @see {@link toSvg}
* @return {Promise} - A promise that is fulfilled with a PNG image data URL
* */
function toPng (node, options) {
return draw(node, options || {})
.then(function (canvas) {
return canvas.toDataURL();
});
}
/**
* @param {Node} node - The DOM Node object to render
* @param {Object} options - Rendering options, @see {@link toSvg}
* @return {Promise} - A promise that is fulfilled with a JPEG image data URL
* */
function toJpeg (node, options) {
options = options || {};
return draw(node, options)
.then(function (canvas) {
return canvas.toDataURL('image/jpeg', options.quality || 1.0);
});
}
/**
* @param {Node} node - The DOM Node object to render
* @param {Object} options - Rendering options, @see {@link toSvg}
* @return {Promise} - A promise that is fulfilled with a PNG image blob
* */
function toBlob (node, options) {
return draw(node, options || {})
.then(util.canvasToBlob);
}
function copyOptions (options) {
// Copy options to impl options for use in impl
if (typeof (options.imagePlaceholder) === 'undefined') {
domtoimage.impl.options.imagePlaceholder = defaultOptions.imagePlaceholder;
} else {
domtoimage.impl.options.imagePlaceholder = options.imagePlaceholder;
}
if (typeof (options.cacheBust) === 'undefined') {
domtoimage.impl.options.cacheBust = defaultOptions.cacheBust;
} else {
domtoimage.impl.options.cacheBust = options.cacheBust;
}
}
function draw (domNode, options) {
return toSvg(domNode, options)
.then(util.makeImage)
.then(util.delay(100))
.then(function (image) {
var canvas = newCanvas(domNode);
canvas.getContext('2d').drawImage(image, 0, 0);
return canvas;
});
function newCanvas (domNode) {
var canvas = document.createElement('canvas');
var ctx = canvas.getContext('2d');
ctx.mozImageSmoothingEnabled = false;
ctx.webkitImageSmoothingEnabled = false;
ctx.msImageSmoothingEnabled = false;
ctx.imageSmoothingEnabled = false;
var scale = options.scale || 1; // 默认值1
canvas.width = (options.width * scale) || util.width(domNode);
canvas.height = (options.height * scale) || util.height(domNode);
ctx.scale(scale, scale) // 添加了scale参数
if (options.bgcolor) {
ctx.fillStyle = options.bgcolor;
ctx.fillRect(0, 0, canvas.width, canvas.height);
}
return canvas;
}
}
function cloneNode (node, filter, root) {
if (!root && filter && !filter(node)) return Promise.resolve();
return Promise.resolve(node)
.then(makeNodeCopy)
.then(function (clone) {
return cloneChildren(node, clone, filter);
})
.then(function (clone) {
return processClone(node, clone);
});
function makeNodeCopy (node) {
if (node instanceof HTMLCanvasElement) return util.makeImage(node.toDataURL());
return node.cloneNode(false);
}
function cloneChildren (original, clone, filter) {
var children = original.childNodes;
if (children.length === 0) return Promise.resolve(clone);
return cloneChildrenInOrder(clone, util.asArray(children), filter)
.then(function () {
return clone;
});
function cloneChildrenInOrder (parent, children, filter) {
var done = Promise.resolve();
children.forEach(function (child) {
done = done
.then(function () {
return cloneNode(child, filter);
})
.then(function (childClone) {
if (childClone) parent.appendChild(childClone);
});
});
return done;
}
}
function processClone (original, clone) {
if (!(clone instanceof Element)) return clone;
return Promise.resolve()
.then(cloneStyle)
.then(clonePseudoElements)
.then(copyUserInput)
.then(fixSvg)
.then(function () {
return clone;
});
function cloneStyle () {
copyStyle(window.getComputedStyle(original), clone.style);
function copyStyle (source, target) {
if (source.cssText) target.cssText = source.cssText;
else copyProperties(source, target);
function copyProperties (source, target) {
util.asArray(source).forEach(function (name) {
target.setProperty(
name,
source.getPropertyValue(name),
source.getPropertyPriority(name)
);
});
}
}
}
function clonePseudoElements () {
[':before', ':after'].forEach(function (element) {
clonePseudoElement(element);
});
function clonePseudoElement (element) {
var style = window.getComputedStyle(original, element);
var content = style.getPropertyValue('content');
if (content === '' || content === 'none') return;
var className = util.uid();
clone.className = clone.className ' ' className;
var styleElement = document.createElement('style');
styleElement.appendChild(formatPseudoElementStyle(className, element, style));
clone.appendChild(styleElement);
function formatPseudoElementStyle (className, element, style) {
var selector = '.' className ':' element;
var cssText = style.cssText ? formatCssText(style) : formatCssProperties(style);
return document.createTextNode(selector '{' cssText '}');
function formatCssText (style) {
var content = style.getPropertyValue('content');
return style.cssText ' content: ' content ';';
}
function formatCssProperties (style) {
return util.asArray(style)
.map(formatProperty)
.join('; ') ';';
function formatProperty (name) {
return name ': '
style.getPropertyValue(name)
(style.getPropertyPriority(name) ? ' !important' : '');
}
}
}
}
}
function copyUserInput () {
if (original instanceof HTMLTextAreaElement) clone.innerHTML = original.value;
if (original instanceof HTMLInputElement) clone.setAttribute("value", original.value);
}
function fixSvg () {
if (!(clone instanceof SVGElement)) return;
clone.setAttribute('xmlns', 'http://www.w3.org/2000/svg');
if (!(clone instanceof SVGRectElement)) return;
['width', 'height'].forEach(function (attribute) {
var value = clone.getAttribute(attribute);
if (!value) return;
clone.style.setProperty(attribute, value);
});
}
}
}
function embedFonts (node) {
return fontFaces.resolveAll()
.then(function (cssText) {
var styleNode = document.createElement('style');
node.appendChild(styleNode);
styleNode.appendChild(document.createTextNode(cssText));
return node;
});
}
function inlineImages (node) {
return images.inlineAll(node)
.then(function () {
return node;
});
}
function makeSvgDataUri (node, width, height) {
return Promise.resolve(node)
.then(function (node) {
node.setAttribute('xmlns', 'http://www.w3.org/1999/xhtml');
return new XMLSerializer().serializeToString(node);
})
.then(util.escapeXhtml)
.then(function (xhtml) {
return '<foreignObject x="0" y="0" width="100%" height="100%">' xhtml '</foreignObject>';
})
.then(function (foreignObject) {
return '<svg xmlns="http://www.w3.org/2000/svg" width="' width '" height="' height '">'
foreignObject '</svg>';
})
.then(function (svg) {
return 'data:image/svg xml;charset=utf-8,' svg;
});
}
function newUtil () {
return {
escape: escape,
parseExtension: parseExtension,
mimeType: mimeType,
dataAsUrl: dataAsUrl,
isDataUrl: isDataUrl,
canvasToBlob: canvasToBlob,
resolveUrl: resolveUrl,
getAndEncode: getAndEncode,
uid: uid(),
delay: delay,
asArray: asArray,
escapeXhtml: escapeXhtml,
makeImage: makeImage,
width: width,
height: height
};
function mimes () {
/*
* Only WOFF and EOT mime types for fonts are 'real'
* see http://www.iana.org/assignments/media-types/media-types.xhtml
*/
var WOFF = 'application/font-woff';
var JPEG = 'image/jpeg';
return {
'woff': WOFF,
'woff2': WOFF,
'ttf': 'application/font-truetype',
'eot': 'application/vnd.ms-fontobject',
'png': 'image/png',
'jpg': JPEG,
'jpeg': JPEG,
'gif': 'image/gif',
'tiff': 'image/tiff',
'svg': 'image/svg xml'
};
}
function parseExtension (url) {
var match = /.([^./]*?)$/g.exec(url);
if (match) return match[1];
else return '';
}
function mimeType (url) {
var extension = parseExtension(url).toLowerCase();
return mimes()[extension] || '';
}
function isDataUrl (url) {
return url.search(/^(data:)/) !== -1;
}
function toBlob (canvas) {
return new Promise(function (resolve) {
var binaryString = window.atob(canvas.toDataURL().split(',')[1]);
var length = binaryString.length;
var binaryArray = new Uint8Array(length);
for (var i = 0; i < length; i )
binaryArray[i] = binaryString.charCodeAt(i);
resolve(new Blob([binaryArray], {
type: 'image/png'
}));
});
}
function canvasToBlob (canvas) {
if (canvas.toBlob)
return new Promise(function (resolve) {
canvas.toBlob(resolve);
});
return toBlob(canvas);
}
function resolveUrl (url, baseUrl) {
var doc = document.implementation.createHTMLDocument();
var base = doc.createElement('base');
doc.head.appendChild(base);
var a = doc.createElement('a');
doc.body.appendChild(a);
base.href = baseUrl;
a.href = url;
return a.href;
}
function uid () {
var index = 0;
return function () {
return 'u' fourRandomChars() index ;
function fourRandomChars () {
/* see http://stackoverflow.com/a/6248722/2519373 */
return ('0000' (Math.random() * Math.pow(36, 4) << 0).toString(36)).slice(-4);
}
};
}
function makeImage (uri) {
return new Promise(function (resolve, reject) {
var image = new Image();
image.onload = function () {
resolve(image);
};
image.onerror = reject;
image.src = uri;
});
}
function getAndEncode (url) {
var TIMEOUT = 30000;
if (domtoimage.impl.options.cacheBust) {
// Cache bypass so we dont have CORS issues with cached images
// Source: https://developer.mozilla.org/en/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest#Bypassing_the_cache
url = ((/?/).test(url) ? "&" : "?") (new Date()).getTime();
}
return new Promise(function (resolve) {
var request = new XMLHttpRequest();
request.onreadystatechange = done;
request.ontimeout = timeout;
request.responseType = 'blob';
request.timeout = TIMEOUT;
request.open('GET', url, true);
request.send();
var placeholder;
if (domtoimage.impl.options.imagePlaceholder) {
var split = domtoimage.impl.options.imagePlaceholder.split(/,/);
if (split && split[1]) {
placeholder = split[1];
}
}
function done () {
if (request.readyState !== 4) return;
if (request.status !== 200) {
if (placeholder) {
resolve(placeholder);
} else {
fail('cannot fetch resource: ' url ', status: ' request.status);
}
return;
}
var encoder = new FileReader();
encoder.onloadend = function () {
var content = encoder.result.split(/,/)[1];
resolve(content);
};
encoder.readAsDataURL(request.response);
}
function timeout () {
if (placeholder) {
resolve(placeholder);
} else {
fail('timeout of ' TIMEOUT 'ms occured while fetching resource: ' url);
}
}
function fail (message) {
console.error(message);
resolve('');
}
});
}
function dataAsUrl (content, type) {
return 'data:' type ';base64,' content;
}
function escape (string) {
return string.replace(/([.* ?^${}()|[]/\])/g, '\$1');
}
function delay (ms) {
return function (arg) {
return new Promise(function (resolve) {
setTimeout(function () {
resolve(arg);
}, ms);
});
};
}
function asArray (arrayLike) {
var array = [];
var length = arrayLike.length;
for (var i = 0; i < length; i ) array.push(arrayLike[i]);
return array;
}
function escapeXhtml (string) {
return string.replace(/#/g, '#').replace(/n/g, '
');
}
function width (node) {
var leftBorder = px(node, 'border-left-width');
var rightBorder = px(node, 'border-right-width');
return node.scrollWidth leftBorder rightBorder;
}
function height (node) {
var topBorder = px(node, 'border-top-width');
var bottomBorder = px(node, 'border-bottom-width');
return node.scrollHeight topBorder bottomBorder;
}
function px (node, styleProperty) {
var value = window.getComputedStyle(node).getPropertyValue(styleProperty);
return parseFloat(value.replace('px', ''));
}
}
function newInliner () {
var URL_REGEX = /url(['"]?([^'"] ?)['"]?)/g;
return {
inlineAll: inlineAll,
shouldProcess: shouldProcess,
impl: {
readUrls: readUrls,
inline: inline
}
};
function shouldProcess (string) {
return string.search(URL_REGEX) !== -1;
}
function readUrls (string) {
var result = [];
var match;
while ((match = URL_REGEX.exec(string)) !== null) {
result.push(match[1]);
}
return result.filter(function (url) {
return !util.isDataUrl(url);
});
}
function inline (string, url, baseUrl, get) {
return Promise.resolve(url)
.then(function (url) {
return baseUrl ? util.resolveUrl(url, baseUrl) : url;
})
.then(get || util.getAndEncode)
.then(function (data) {
return util.dataAsUrl(data, util.mimeType(url));
})
.then(function (dataUrl) {
return string.replace(urlAsRegex(url), '$1' dataUrl '$3');
});
function urlAsRegex (url) {
return new RegExp('(url\(['"]?)(' util.escape(url) ')(['"]?\))', 'g');
}
}
function inlineAll (string, baseUrl, get) {
if (nothingToInline()) return Promise.resolve(string);
return Promise.resolve(string)
.then(readUrls)
.then(function (urls) {
var done = Promise.resolve(string);
urls.forEach(function (url) {
done = done.then(function (string) {
return inline(string, url, baseUrl, get);
});
});
return done;
});
function nothingToInline () {
return !shouldProcess(string);
}
}
}
function newFontFaces () {
return {
resolveAll: resolveAll,
impl: {
readAll: readAll
}
};
function resolveAll () {
return readAll(document)
.then(function (webFonts) {
return Promise.all(
webFonts.map(function (webFont) {
return webFont.resolve();
})
);
})
.then(function (cssStrings) {
return cssStrings.join('n');
});
}
function readAll () {
return Promise.resolve(util.asArray(document.styleSheets))
.then(getCssRules)
.then(selectWebFontRules)
.then(function (rules) {
return rules.map(newWebFont);
});
function selectWebFontRules (cssRules) {
return cssRules
.filter(function (rule) {
return rule.type === CSSRule.FONT_FACE_RULE;
})
.filter(function (rule) {
return inliner.shouldProcess(rule.style.getPropertyValue('src'));
});
}
function getCssRules (styleSheets) {
var cssRules = [];
styleSheets.forEach(function (sheet) {
try {
util.asArray(sheet.cssRules || []).forEach(cssRules.push.bind(cssRules));
} catch (e) {
console.log('Error while reading CSS rules from ' sheet.href, e.toString());
}
});
return cssRules;
}
function newWebFont (webFontRule) {
return {
resolve: function resolve () {
var baseUrl = (webFontRule.parentStyleSheet || {}).href;
return inliner.inlineAll(webFontRule.cssText, baseUrl);
},
src: function () {
return webFontRule.style.getPropertyValue('src');
}
};
}
}
}
function newImages () {
return {
inlineAll: inlineAll,
impl: {
newImage: newImage
}
};
function newImage (element) {
return {
inline: inline
};
function inline (get) {
if (util.isDataUrl(element.src)) return Promise.resolve();
return Promise.resolve(element.src)
.then(get || util.getAndEncode)
.then(function (data) {
return util.dataAsUrl(data, util.mimeType(element.src));
})
.then(function (dataUrl) {
return new Promise(function (resolve, reject) {
element.onload = resolve;
element.onerror = reject;
element.src = dataUrl;
});
});
}
}
function inlineAll (node) {
if (!(node instanceof Element)) return Promise.resolve(node);
return inlineBackground(node)
.then(function () {
if (node instanceof HTMLImageElement)
return newImage(node).inline();
else
return Promise.all(
util.asArray(node.childNodes).map(function (child) {
return inlineAll(child);
})
);
});
function inlineBackground (node) {
var background = node.style.getPropertyValue('background');
if (!background) return Promise.resolve(node);
return inliner.inlineAll(background)
.then(function (inlined) {
node.style.setProperty(
'background',
inlined,
node.style.getPropertyPriority('background')
);
})
.then(function () {
return node;
});
}
}
}
})(this);在使用的地方直接添加参数
代码语言：javascript复制// 跳转到生成名片
clickGeneratePictureBydomtoimage(){
console.log('clickGeneratePictureBydomtoimage')
var that = this;
var index = that.activeIndex;
let node = document.getElementsByClassName("mint-swipe-item")[index]
var options = {
width:375, // 高度宽度自行设定
height:450,
scale:8
}
domtoimage.toPng(node, options)
.then(function (dataUrl) {
//do something
})
.catch(function (error) {
console.error('oops, something went wrong!', error);
});
}
